JP5229241B2 - Temperature sensor mounting structure in semiconductor manufacturing equipment - Google Patents

Description

  The present invention relates to a wafer heating apparatus to which a resistance temperature detector element is attached and a semiconductor manufacturing apparatus on which the wafer heating apparatus is mounted.

  In a semiconductor manufacturing apparatus such as a CVD apparatus or a plasma CVD apparatus, a heated semiconductor wafer is subjected to processing such as etching and film formation. In that case, since a higher quality semiconductor product can be obtained by heating the wafer uniformly, the wafer mounting surface is generally placed on one surface of a disk-shaped member made of metal, ceramics or the like having high thermal conductivity. While being provided, a wafer heating apparatus having a resistance heating element on the other surface is used.

  A wafer heating device having such a structure is generally equipped with a temperature measuring element such as a thermocouple or a resistance temperature detector, and the voltage and current applied to the resistance heating element are adjusted based on the temperature measured by the temperature measuring element. By doing so, temperature control of the wafer heating apparatus is performed. This temperature control may be affected by the mounting structure of the temperature measuring element in the wafer heating apparatus. For example, the accuracy and response may be affected by the mounting structure. For this reason, various devices have been conventionally made in the temperature sensor mounting structure.

  For example, in Patent Document 1, in a heated body such as a susceptor having a wafer mounting surface, a bottomed hole is provided on a surface opposite to the wafer mounting surface, and in a chamber that houses the heated body. A structure is disclosed in which a bellows is provided at a position corresponding to the bottomed hole, and the tip of the thermocouple is pressed against the bottom surface of the bottomed hole by the urging force of the bellows. It is described that this structure enables highly accurate and stable temperature measurement.

  In Patent Document 2, a holding member such as a sheath for holding a thermocouple is screwed into a bottomed hole provided in a heated body such as a susceptor, and the tip of the thermocouple is exposed from the holding member. A structure for directly contacting the object to be heated is disclosed, and it is described that the temperature measurement time can be shortened.

JP 2009-042070 A JP 2004-132702 A

  In recent years, demands for improving the yield of semiconductor products manufactured in a semiconductor manufacturing apparatus have become strict, and accordingly, temperature management on the wafer mounting surface of the wafer heating apparatus has also become strict. That is, a wafer heating apparatus capable of highly accurate and responsive temperature control while maintaining the thermal uniformity on the wafer mounting surface is becoming more important. There is also a demand for a wafer heating apparatus capable of rapid heating in order to improve throughput.

  However, since the wafer heating apparatus described in Patent Document 1 and Patent Document 2 described above has a structure in which the tip of the temperature measuring element is inserted into a bottomed hole provided in the object to be heated, A resistance heating element cannot be provided in the provided portion, and this portion becomes a so-called cool spot, which is a cause of deterioration in heat uniformity on the wafer mounting surface.

  The present invention has been made in view of such conventional circumstances, and is capable of rapid heating and is excellent in heat uniformity on the wafer mounting surface, and is capable of highly accurate and responsive temperature control. An object of the present invention is to provide a wafer heating apparatus that can be used.

In order to achieve the above object, a wafer heating apparatus provided by the present invention includes a soaking plate having a wafer mounting surface on one surface and a circuit of a resistance heating element on the other surface, and a soaking plate of the soaking plate. A temperature measuring resistor element for measuring temperature, and the soaking plate includes a digging portion for embedding the temperature sensing resistor element on the other surface side and a lid plate for covering the digging portion. The resistance temperature detector element is embedded in close contact with the bottom surface of the digging portion without being covered .

  According to the present invention, it is possible to provide a wafer heating apparatus that can perform rapid heating and has excellent heat uniformity on the wafer mounting surface, and can perform temperature control with high accuracy and good response.

1 is a schematic cross-sectional view showing a first embodiment of a wafer heating apparatus of the present invention. It is a partial expanded sectional view which shows one specific example of the attachment structure of the resistance temperature element in the wafer heating apparatus of this invention. It is a partial expanded sectional view which shows the other specific example of the attachment structure of the resistance thermometer element in the wafer heating apparatus of this invention. It is a partial expanded sectional view which shows 2nd Embodiment of the wafer heating apparatus of this invention. It is the elements A1 and B1 of an Example, and the elements on larger scale which each show the attachment structure of the resistance temperature detector element in the wafer heating apparatus of A2 and B2. It is the elements A3 and B3 of an Example, and the elements on larger scale which respectively show the attachment structure of the resistance temperature detector element in the wafer heating apparatus of A4 and B4. It is the elements A5 and B5 of an Example, and the elements on larger scale which respectively show the attachment structure of the resistance temperature detector element in the wafer heating apparatus of A6 and B6.

  Hereinafter, the wafer heating apparatus of the present invention will be specifically described with reference to the drawings. FIG. 1 shows a wafer heating apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the wafer heating apparatus according to the first embodiment of the present invention has a flat plate-shaped soaking plate 10. The soaking plate 10 is preferably formed of a metal having a high thermal conductivity such as a metal such as Cu or a ceramic such as AlN.

  The upper surface of the soaking plate 10 is a wafer mounting surface 10a, on which the wafer W is mounted and subjected to processing such as etching and film formation. A resistance heating element 20 is formed on the lower surface of the soaking plate 10, that is, the surface opposite to the wafer mounting surface 10a. A lead wire for power supply (not shown) is connected to the resistance heating element 20, and the resistance heating element 20 generates heat by supplying power to the resistance heating element 20 through the lead wire, thereby placing the wafer on the wafer. The wafer W placed on the surface 10a can be heated.

  The soaking plate 10 has one or more resistance temperature detector elements 30. The temperature measuring resistor element 30 measures the temperature of the soaking plate 10, and the amount of current supplied to the resistance heating element 20 is adjusted based on the measured temperature. Although four resistance temperature detector elements 30 are illustrated in FIG. 1, the number of resistance temperature detector elements 30 is not limited to this.

  Next, the structure in which the resistance thermometer element 30 is attached to the soaking plate 10 will be described in more detail. FIG. 2 is a partial enlarged cross-sectional view showing an attachment structure for an arbitrary one of the four resistance temperature detector elements 30 shown in FIG. As shown in FIG. 2, the soaking plate 10 has a digging portion 11 on the surface opposite to the wafer mounting surface 10a, in which the entire resistance temperature detector element 30 can be embedded. Yes.

  The size of the dug portion 11 is preferably as small as possible. Specifically, when the dug portion 11 is viewed from the lower side of the soaking plate 10, the dug portion 11 is preferably dug into a shape that substantially matches the outer shape of the resistance temperature detector element 30. Thereby, the close_contact | adherence degree of the resistance temperature detector element 30 and the soaking | uniform-heating plate 10 increases, and the temperature of the soaking | uniform-heating plate 10 can be measured correctly and rapidly. Further, it is possible to suppress a decrease in heat uniformity on the wafer placement surface 10a and to keep the size of the cool spot to a minimum.

  As shown in FIG. 2, the shape of the bottom of the digging portion 11 is preferably a rectangular shape having a constant depth in a cross section perpendicular to the wafer mounting surface 10a. Thereby, when the resistance thermometer element 30 is embedded in the digging portion 11, the longitudinal direction is substantially parallel to the wafer placement surface 10 a of the soaking plate 10, so that the resistance thermometer element 30 is In the buried region, the ratio of the dug portion 11 occupying in the thickness direction of the soaking plate 10 can be minimized. As a result, the entire resistance temperature detector element 30 can be embedded without increasing the thickness of the soaking plate 10, and the soaking plate 10 can be heated and cooled at high speed.

  As a fixing method of the resistance temperature detector element 30, it may be fixed to the heat equalizing plate 10 with an adhesive applied to the bottom surface or inner wall of the digging portion 11, or a heat equalizing plate using a coupling means such as a screw. 10 may be fixed. Moreover, you may fix by pinching with the cover plate 13 mentioned later and the bottom face of the digging part 11. FIG.

  By the way, as shown in FIG. 2, the general resistance thermometer element 30 is comprised from the elongate main-body part 31, and the detection part 32 which protrudes from the one end part, and the thickness of the detection part 32 is the same. It is formed thinner than the main body portion 31. When the resistance temperature detector element 30 having such a structure is embedded in the rectangular digging portion 11 having a constant depth, the detection portion 32 is separated from the bottom surface 11a of the digging portion 11 and the soaking plate 10 There is a risk that the temperature cannot be detected accurately and quickly.

  This problem can be dealt with by filling the gap between the detection portion 32 and the bottom surface 11a of the digging portion 11 with the filler 12 having high thermal conductivity. Alternatively, a plate-like member having a high thermal conductivity such as metal or ceramic may be sandwiched between the gaps as a spacer.

  Further, as shown in FIG. 3, a step 11 b may be formed at the bottom of the digging portion 11 so as to substantially match the outer shape of the resistance temperature detector element 30 when buried. Thereby, since the detection part 32 of the resistance thermometer element 30 can be made to closely_contact | adhere to the soaking | uniform-heating plate 10, temperature can be detected more correctly and rapidly. In addition, it is desirable that the mutually opposing surfaces of the step 11b portion and the detection portion 32 have a shape that can be contacted over as wide a range as possible. For example, when the facing part of the detection part 32 has a flat shape, it is preferable that the facing part of the step 11b facing the detecting part 32 also has a flat shape.

  The opening of the digging portion 11 is covered with a lid plate 13. Accordingly, the resistance temperature detector element 30 provided along the bottom surface 11 a of the digging portion 11 is covered with the lid plate 13. The lid plate 13 preferably has a flat plate shape that can be fitted into the opening of the digging portion 11. Specifically, when the lid plate 13 fitted in the opening of the digging portion 11 is viewed from the lower side of the soaking plate 10, the digging portion 11 except for a hole for a lead wire 40 described later. It is preferable to have a shape that closes the opening without any gap. Thereby, it is possible to further suppress the decrease in the thermal uniformity of the wafer mounting surface 10a and the generation of cool spots in the region where the resistance temperature detector element 30 is embedded.

  Furthermore, when the lid plate 13 is fitted into the opening of the digging portion 11 so as to cover the resistance temperature detector element 30, the side opposite to the lower surface of the lid plate 13, that is, the surface facing the digging portion 11. Is preferably on the same plane as the lower surface of the soaking plate 10. This facilitates the formation of the resistance heating element 20 on the lower surface of the lid plate 13 to be described later, and facilitates the installation of a back plate that covers it. The material of the lid plate 13 is not particularly limited, but is preferably the same as that of the soaking plate 10 from the viewpoint of soaking.

  A lead wire 40 that outputs a signal measured by the detection portion 32 is connected to the resistance temperature detector 30 at the end opposite to the end from which the detection portion 32 protrudes. In order to pass the lead wire 40, the lid plate 13 is preferably provided with a through hole or a notch. FIG. 2 shows a state in which the lead wire 40 extends to the outside of the soaking plate 10 through a notch provided in the lid plate 13.

  The method for fixing the lid plate 13 to the soaking plate 10 is not particularly limited. For example, the soaking plate 10 or the resistance temperature detector element 30 using a mechanical means such as a screw or a chemical means such as an adhesive, Or it can be fixed to both. The shape of the lid plate 13 may be a flat plate shape having a predetermined thickness as described above. In this case, as in the case of the rectangular digging portion 11 having a certain depth described above, the resistance temperature detector Depending on the shape of the body element 30, the lid plate 13 and the detection portion 32 may be separated from each other, and the temperature may not be detected accurately and quickly.

  Also in this case, like the rectangular digging portion 11 described above, the filler 12 having a high thermal conductivity is filled in the gap between the detection portion 32 and the lid plate 13, or the thermal conductivity is used as a spacer in the gap. A plate-like member having a high height may be sandwiched. Alternatively, as shown in FIG. 3, a step 13 a may be formed on the surface of the lid plate 13 that faces the digging portion 11 so as to substantially match the outer shape of the resistance temperature detector element 30.

  It is preferable that a circuit of the resistance heating element 20 is formed partially or entirely on the lower surface of the lid plate 13, that is, the surface opposite to the surface facing the digging portion 11. In the case of partial formation, it is particularly preferable to form the circuit of the resistance heating element 20 in the lower part of the detection part 32. As a result, cool spots are less likely to be generated, and the thermal uniformity on the wafer mounting surface 10a can be further enhanced. Further, by forming a circuit of the resistance heating element 20 on the lower surface of the lid plate 13, it is possible to perform control with high accuracy and good response.

  Next, a wafer heating apparatus according to a second embodiment of the present invention will be described with reference to FIG. The wafer heating apparatus according to the second embodiment is characterized in that a back plate 50 is provided on the lower side of the soaking plate 10, that is, on the side opposite to the wafer mounting surface 10 a so as to cover the resistance heating element 20. It is said. The method for fixing the back plate 50 is not particularly limited, and the back plate 50 can be fixed to the soaking plate 10 by using general coupling means such as screwing, vacuum suction, and adhesive.

  The material of the back plate 50 can be a metal such as Cu or a ceramic such as AlN, but is preferably different from the material of the soaking plate 10. For example, it is desirable to form the soaking plate 10 from a metal such as Cu and the back plate 50 from a ceramic having a high Young's modulus such as AlN, Si—SiC, or Al—SiC. Accordingly, it is possible to cause each member to play the role of heat uniformity on the wafer mounting surface and the role of rigidity, and it is possible to manufacture a wafer heating apparatus having both high heat uniformity and high rigidity.

  By providing the back plate 50 on the lower side of the soaking plate 10 in this way, the resistance heating element 20 can be sandwiched between the soaking plate 10 and the back plate 50. Can be distributed to the soaking plate 10 more efficiently. In FIG. 4, since the circuit of the resistance heating element 20 is partially formed on the lower surface of the lid plate 13, the back plate 50 replaces the resistance heating element 20 formed on the lower surface of the lid plate 13. Also has a shape to cover. On the other hand, when the circuit of the resistance heating element 20 is not formed on the lower surface of the lid plate 13, the back plate 50 may have a shape that exposes the entire lower surface of the lid plate 13.

  The wafer heating apparatus having the temperature measuring resistor element mounting structure described above is mounted on a semiconductor manufacturing apparatus such as a CVD apparatus or a plasma CVD apparatus, and serves as a mounting table for uniformly heating a wafer to be processed. At that time, rapid heating is possible and excellent temperature uniformity on the wafer mounting surface, and high-precision and responsive temperature control can be performed, so high-quality semiconductor products can be manufactured with high throughput. It becomes possible to do.

  In particular, by adopting the RTD element mounting structure described above, a resistance heating element is provided below the RTD element, particularly immediately below the detection part most susceptible to temperature detection. Therefore, it is possible to provide a wafer heating apparatus that is extremely excellent in control accuracy and response and excellent in temperature uniformity on the wafer mounting surface. In addition, in the related art, it has been a problem when a temperature measuring element such as a temperature measuring resistance element is installed on the heat equalizing plate, and the resistance heating element cannot be provided at the lower part of the installation part. The problem of cool spots can be solved.

  As mentioned above, although the specific example was given and demonstrated about the wafer heating apparatus of this invention, and the semiconductor manufacturing apparatus provided with the same, this invention is not limited to such a specific example, In the range which does not deviate from the main point of this invention It can be implemented in various ways. That is, the technical scope of the present invention extends to the claims and their equivalents.

[Example 1]
As shown in FIG. 5 to FIG. 7, wafer heating devices of samples A1 to A6 having different mounting structures of resistance temperature detector elements were prepared, and their thermal uniformity and control performance were tested. Specifically, a Cu plate having a thickness of 3 mm and a diameter of 320 mm is prepared as a soaking plate, and a rectangular shape having a constant depth of 4 mm in width, 10 mm in length, and 2.3 mm in depth without a step is provided on the lower surface side. A resistance temperature detector element (JIS standard, PT100) was installed so as to provide a digging portion and be in close contact with the bottom surface. A gap formed between the dug portion and the resistance temperature detector element was filled with a filler (manufactured by Toray, model number: SE1714BK).

  Next, as a lid plate, a Cu flat plate having a thickness of 0.7 mm was processed into a shape that fits into the opening of the digging portion. This was fitted into the digging portion to cover the resistance temperature detector element. The lid plate was fixed to the soaking plate using the same filler as described above. Further, the gap formed between the lid plate and the resistance temperature detector element was filled with the same filler as described above.

  Furthermore, a circuit formed by sandwiching a resistance heating element made of stainless steel foil with a polyimide foil was formed in a region other than the dug portion on the lower surface of the soaking plate. In this way, a wafer heating apparatus for sample A1 shown in FIG.

  As shown in FIG. 5B, the wafer heating apparatus for sample A2 is the same as the above except that the resistance heating element circuit is also formed on the lower surface of the lid plate and below the detection portion of the resistance temperature detector element. It was produced in the same manner as Sample A1. Further, as shown in FIGS. 6 (a) and 6 (b), the wafer heating apparatus for samples A3 and A4 is provided with a back plate on the lower surface side of the soaking plate so as to cover the circuit of the resistance heating element. Were prepared in the same manner as Samples A1 and A2, respectively.

  Note that Si-SiC flat plates having a thickness of 3 mm and a diameter of 320 mm were used for these back plates. The back plate of sample A3 is processed so that the lower surface of the lid plate is exposed entirely, and the back plate of sample A4 is exposed only on the lower surface of the lid plate where the circuit of the resistance heating element is not formed. Processed to. Furthermore, these back plates were each mechanically joined to the lower surface side of the soaking plate by screwing.

  As shown in FIGS. 7A and 7B, the wafer heating devices for samples A5 and A6 are in contact with the detection portion of the resistance temperature detector element on the bottom surface of the digging portion and the top surface of the lid plate, respectively. These were prepared in the same manner as Samples A3 and A4, respectively, except that a step with a height of 0.5 mm was provided.

  With respect to the wafer heating devices of these samples A1 to A6, a control loop is assembled so that the amount of electricity supplied to the resistance heating element is automatically adjusted according to the output value from the resistance temperature detector element. The method was tested for control response and thermal uniformity on the wafer mounting surface. In addition, in order to suppress the influence of disturbances, such as the airflow of external air, the whole wafer heating apparatus was covered with the SUS board of thickness 1mm.

  First, the set temperature of the control system was set to 130 ° C., and the soaking plate was heated by supplying power to the resistance heating element of the wafer heating apparatus. After confirming that the temperature measured by the resistance thermometer element is stable at 130 ° C., the temperature distribution in the 300 mm diameter zone where the resistance thermometer element is embedded on the wafer mounting surface is 65 points. Measurement was performed using a wafer thermometer. After the measurement, a 12-inch silicon wafer was placed on the wafer placement surface, and the change over time of the temperature measured by the resistance temperature detector element was recorded.

  The results of these tests are shown in Table 1 below. Here, the amount of overshoot at the time of recovery means the maximum fluctuation width from the set temperature of 130 ° C. after the wafer is placed on the wafer placement surface. The recovery time after placing the wafer refers to the time required to stabilize again at 130 ° C. after placing the wafer on the wafer placement surface. The temperature distribution means a difference between the highest temperature and the lowest temperature among the temperatures measured at a plurality of locations in the zone.

[Example 2]
A wafer heating apparatus for samples B1 to B6 is manufactured in the same manner as in Example 1 except that the material of the soaking plate and lid plate is Al instead of Cu, and the material of the back plate is AlN instead of Si-SiC. did. The same tests as in Example 1 were performed on the wafer heating apparatuses of Samples B1 to B6. The test results are shown in Table 2 below.

  As shown in Table 1, samples A1 and A2, Samples A3 and A4, and Samples A5 and A6, and Samples B1 and B2, Samples B3 and B4, and Samples B5 and B6 in Table 2 are compared. By providing a resistance heating element in a portion located almost directly below the detection portion of the temperature resistor element, the amount of overshoot during recovery and the recovery time after placing the wafer could be suppressed. Furthermore, higher soaking properties could be obtained. In addition, as can be seen by comparing the samples A1 and A3 and samples A2 and A4 in Table 1 and the samples B1 and B3 and Samples B2 and B4 in Table 2 above, by providing a back plate, so-called heat can be obtained. The spreader effect was obtained, and it was confirmed that there was a better influence on the thermal uniformity on the wafer mounting surface. Furthermore, the recovery time after placing the wafer could be shortened.

  Further, as shown in Table 1, samples A3 and A5, Samples A4 and A6, and Samples B3 and B5 in Table 2 and Samples B4 and B6, respectively, are digged to embed a resistance temperature detector element. The control response was improved by providing a step in the recessed portion and the lid plate. This is because the heat transfer resistance at the time of heat transfer to the detection portion is reduced by securely sandwiching the detection portion between the two step portions, and the temperature of the soaking plate can be detected more accurately and quickly. it is conceivable that. In addition, the superiority in the thermal uniformity was confirmed, and the recovery time after placing the wafer could be shortened, and it was found that the result of greatly contributing to the thermal uniformity of the wafer temperature and the control performance was obtained.

DESCRIPTION OF SYMBOLS 10 Soaking | uniform-heating plate 10a Wafer mounting surface 11 Digging part 11a Bottom face of digging part 11b Level difference of digging part 12 Filler 13 Lid plate 13a Level difference of lid plate 20 Resistance heating element 30 Resistance temperature detector element 31 Main body part 32 Detection part 40 Lead wire 50 Back plate W Wafer

Claims (5)

A wafer heating apparatus comprising a soaking plate having a wafer mounting surface on one surface and a resistance heating element circuit on the other surface, and a resistance thermometer element for measuring the temperature of the soaking plate. The soaking plate is provided with a digging portion for embedding the resistance temperature detector element on the other surface side and a lid plate for covering the digging portion, and the resistance temperature sensing element is covered. wafer heating apparatus characterized by being buried in close contact with the bottom surface of the digging portion in absence.   2. The wafer according to claim 1, wherein a part of the circuit of the resistance heating element is present on at least a part of a surface of the lid plate opposite to a surface facing the digging portion. Heating device.   The wafer according to claim 1, wherein the resistance temperature detector element is embedded in the digging portion so that a longitudinal direction thereof is substantially parallel to the wafer mounting surface. Heating device.   The wafer heating apparatus according to claim 1, wherein a back plate that covers a circuit of the resistance heating element is further provided on the other surface side of the soaking plate.   A semiconductor manufacturing apparatus comprising the wafer heating apparatus according to claim 1.

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